The invention relates to a method and a device for regulating the rotational speed of agitator ball mills which have a grinding chamber with grinding balls contained therein, a rotatably mounted agitator body arranged in the grinding chamber and a drive for the agitator body, the rotational speed n of the agitator body being measured.
Agitator ball mills are used, for example, for working powdered solid into liquid media (dispersal) and for the wet grinding of solid materials.
Conventionally, these agitator ball mills run either at a fixed rotational speed or else at a variable rotational speed, this being indicated on a corresponding measuring instrument.
The torque of the agitator shaft is dependent both on the internal parameters of the agitator ball mill and on the nature of the grinding material located in the grinding chamber. In the known agitator ball mills, therefore, changes in the torque of the agitator shaft occur. At high torques, there is the danger that the drive motor for the agitator shaft will be overloaded.
Success of dispersal or comminution during the operation of an agitator ball mill depends on the level of mechanical agitating capacity P. P is determined from the rotational speed n and the torque M of the agitator shaft according to the following equation EQU P=2.pi..multidot.n.multidot.M
where .pi.=3.141 . . .
In the known agitator ball mills, even when n is constant, the agitating capacity undergoes changes because of the changes in M, and therefore the results of the dispersing or comminuting process are not uniform.